The present disclosure relates generally to fluid injection devices. More particularly, the present disclosure relates to injecting fluids into desired objects. For instance, injection devices can be used in the medical or veterinary fields to deliver drugs to a patient or animal. In various other industries, injection devices can be used to inject or deliver various liquids, gases, chemicals, materials, etc. into another body or medium as desired.
Some conventional methods for injecting fluids into a desired object can involve the use of a syringe. One problem with conventional syringes is that a user must first insert the syringe into the desired object, and then manually deliver the fluids into the desired object. A substantial amount of time can lapse between the initial insertion and the completion of the injection process, or fluid delivery. Such a lapse of time can be undesirable when it is beneficial for injection to occur quickly, or if the object being injected is prone to movement during injection. One such instance can be in a patient setting when the patient is uneasy about injections or needles, for instance if the patient is a child or generally has a fear of needles. A lapse of time between insertion of the syringe and delivery of the medicine to the patient affords the patient the opportunity to move or jerk suddenly, which can affect the proper delivery of the drug to the patient and is generally undesirable. Another such instance is a nurse causing lateral movement of a needle in patient tissue while injecting fluid as a result of the nurse having to manually push or pull a plunger to inject fluid while simultaneously attempting to hold the device stationary.
In other injection devices, delivery of the fluid to the desired object can be automated. Some injection devices can utilize complicated hydraulic or pneumatic systems to provide the required force for injecting the fluid into the desired object. Such injection systems can be cumbersome and expensive and are not conducive for certain applications. In still other injection devices, elastic materials such as springs can be used to provide the force necessary to inject the fluid or gas into the desired object. The springs can be compressed in a loaded or cocked state prior to injection. The springs can be released when desired to inject a fluid contained in the injection device into the desired object. However, springs can wear over time with repeated cycles of compression and decompression, such that the injection force, as well as the depth of the injection produced by the injection device, can gradually change. If the injection characteristics of the injection device change over time, the injection device often will need to be repaired, recalibrated, or replaced entirely.
Additionally, when elastic members such as springs are used as the driving force in injection devices, those devices are typically retained in a cocked state, with a spring in either tension or compression prior to actuation, by a locking device or some other mechanism. As a user actuates the device, the user must disengage the locking mechanism by overcoming the large amount of potential energy and force stored in the spring when in the cocked orientation, which can be cumbersome, particularly in situations where injection must occur quickly.
Auto-injectors are often used in a medical setting to deliver a variety of drugs in emergency or life-threatening situations, for instance in patients having allergic reactions, or exposure to poisons, venoms, or other chemicals and agents. Auto-injectors can also be used to quickly and consistently administer medications needing to be delivered frequently, such as with insulin for diabetic patients, or other maintenance type medication protocols. One large market where auto-injectors are utilized is the Epinephrine injection market. Auto-injectors currently used to deliver epinephrine are relatively expensive, with each injector device costing several hundreds of dollars. Additionally, epinephrine degrades over time, and typically must be replaced once a year if not used. The medicine is also very temperature sensitive. For instance, if an epinephrine auto-injector is left in a hot or cold car, the heat could spoil the medicine such that the medicine must be replaced.
Current auto-injectors are single use, self-contained devices that do not allow for medicine to be removed or replaced within the device without completely disassembling the mechanics of the injector device or actuating the entire device. Current devices are difficult or impossible to reload without the help of a medical professional or technical expert. As such, current protocol requires potential consumers of epinephrine injectors to replace the entire expensive auto-injectors once a year, and additionally if the medicine is exposed to varying temperatures or otherwise compromised. However, the medication inside the auto-injector which has spoiled or been compromised is itself relatively inexpensive when compared to the overall cost of current auto-injectors.
Additionally, because medicine within current auto-injectors cannot be removed or replaced easily, a separate auto-injector often must be purchased and maintained for injections of different medications or medication volumes, different infusion rates, or if different types of needles are desired. For instance, in a hospital setting it may be beneficial to have various medications capable of being injected quickly, more consistently, or in a manner that reduces the risk of inadvertent needle sticks. With current auto injector technology, the hospital would need to purchase a separate auto-injector for each type of medication, each medication volume and each type of needle to be used, and replace each periodically, which can become quite expensive for the hospital. As a result, hospitals continue to overwhelmingly use manual syringes to inject fluids despite the higher risk of accidental needle sticks due to the exposed needles of manual syringes and the need for greater skill and dexterity to consistently and safely use a manual syringe.
What is needed then are improvements to conventional injection devices.